Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Niepel, A.
Influence of Short arm Centrifugation on EEG and Orthostatic Tolerance.
[ Diplomarbeit/Master Thesis ] Medizinischen Universität Wien; 2013. pp.74.
- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Goswami Nandu
- Hinghofer-Szalkay Helmut
- Altmetrics:
- Abstract:
- Brain waves are in a state of dynamic change, depending on current psychological and physiological conditions. It is well known that psychological, especially emotional arousal can alter brain wave patterns (1, 2). The question arises as to what happens to EEG or wave frequency during physical arousal such as exercise or cardiovascular stress. Nevertheless, psychological factors and general influences can never be neglected, because they influence brain activity in every case, particularly in challenging environments such as microgravity or hyper-gravity. Recent studies put physical factors more and more into picture, since the influence of emotional arousal has been well proven (1, 2). With equipment becoming increasingly available and usable during spaceflight or centrifugation, examining EEG patterns during exceptional conditions is more accurate and feasible (3-6). Because short arm human centrifuges are considered to be a part of future Space missions, understanding the influence of such artificial gravity on the neurocognitive system is of high importance and could possibly help to improve post-flight symptoms and could contribute therefore to the safety of human Space flight. This study observed the influence of 45 minutes of short arm centrifugation on changes in EEG and orthostatic tolerance during LBNP on a tilt table device. Subjects either went through a control day with 60 minutes of HDT followed by LBNP testing or an intervention day with 60 minutes of HDT followed by a staged centrifugation training protocol individualized for each subject and LBNP afterwards. Beside simple endurance time assessment, FFT (fast Fourier transformation) brain wave analysis and sLORETA (7) brain activity recording was carried out. It was hypothesized that subjects would show a lower stress reaction and would increase their cardiovascular endurance during LBNP testing with previous artificial gravity training application. With previous centrifugation training subjects showed significantly less beta (33.48 %; p=0.005) and less alpha (26.7 %; p=0.043) in the frontal lobe during a 60 second segment (55 seconds before to 5 seconds after reaching presyncope), even though loading of the cardiovascular system was equal in both the protocols. The results suggest that the individualized centrifugation protocol is sufficient to diminish stress levels in the subjects. In addition, the assessment of cortical current density with sLORETA showed a 23.5% reduction of frontal brain activity in the same segment of 60 seconds, which is also suggestive of less stress with centrifuge training. Additionally, subjects showed 8.2% or 68.7 seconds longer orthostatic tolerance endurance on the tilt table with previous short arm centrifugation. Male subjects showed slight, but not significantly, better results than females. This result strengthens the fact that short arm centrifugation is effective to countermeasure cardiovascular deconditioning in space. Improvement in orthostatic tolerance, due to short arm human centrifuge training seems to be reflected also in changed EEG patterns. Understanding the linkage between orthostatic improvement and changes in EEG patterns could enable developing better centrifugation training protocols, which might be used in future missions.